Liz Cheney calls Trump ‘a domestic threat that we have never faced before.’

Representative Liz Cheney, the Wyoming Republican and vice chairwoman of the House committee investigating the Capitol riot of Jan. 6, 2021, described former President Donald J. Trump in stark terms on Wednesday night as a threat to the republic who had “gone to war with the rule of law.”

“At this moment, we are confronting a domestic threat that we have never faced before — and that is a former president who is attempting to unravel the foundations of our constitutional republic,” Ms. Cheney said in a speech at the Ronald Reagan Presidential Library in Simi Valley, Calif., where her address was met with a sustained standing ovation.

“He is aided by Republican leaders and elected officials who made themselves willing hostages to this dangerous and irrational man,” she said, continuing, “Even after all we’ve seen, they’re enabling his lies.”

Ms. Cheney spoke at a moment when Mr. Trump is potentially on the verge of announcing a presidential campaign for 2024, according to his advisers, raising the prospect of a front-running candidate in early polls who is also facing active civil and criminal investigations. Mr. Trump has also continued to repeat lies about his 2020 election loss, maintaining that the contest was “stolen” from him.

“As the full picture is coming into view with the Jan. 6 committee, it has become clear that the efforts Donald Trump oversaw and engaged in were even more chilling and more threatening than we could have imagined,” Ms. Cheney said.

Republicans, she said at another point, “have to choose,” because they “cannot both be loyal to Donald Trump and loyal to the Constitution.”

It was a striking commentary from the daughter of a Republican former vice president, Dick Cheney, against the current leader of the Republican Party, even as he is out of office. Ms. Cheney had been a supporter of Mr. Trump’s until shortly after the 2020 election, when she criticized him for his baseless fraud allegations.

In May 2021, she said she regretted voting for him the previous year.

Ms. Cheney, who was forced out of her leadership post as the No. 3 Republican in the House last year as she repeatedly excoriated Mr. Trump for the events of Jan. 6, has become a fairly isolated presence within a party that remains heavily in thrall of the former president.

She is seen as a potential presidential candidate in the 2024 election, in which she could try to plant a flag showing how the party has morphed from the one her father helped lead into one reshaped by Trumpism.

Ms. Cheney began her speech by talking about undemocratic countries around the world and nations that are adversaries of the United States, including Russia and China. From there, she talked about Mr. Trump.

She praised Cassidy Hutchinson, a former aide to Mark Meadows, Mr. Trump’s last White House chief of staff, for her public testimony in Congress a day earlier.

“Her bravery and patriotism were awesome to behold,” Ms. Cheney said.

Ms. Cheney is facing a Trump-backed primary challenger for her Wyoming congressional seat in August, and the race is widely seen as an uphill battle for her.